You may have heard the joke with the joke-tellers’ club members who yell out numbers at each other and everybody else laughs out loud (see the appendix at the end of the article for a full rendition of the joke). The joke tellers have an incredibly efficient method of communication — instead of telling a whole joke, they use a number to refer to it. They can do so because everybody else knows what they’re talking about. All the common knowledge of previously told jokes helps them be so efficient. This is what common ground is about.

What Is Common Ground?

Common ground is a concept introduced by the psycholinguists Herb Clark and Susan Brennan.

Definition. Common ground refers to the mutual knowledge, beliefs, and assumptions that partners in a conversation rely on in order to communicate efficiently. The process of establishing common ground is called grounding.

Whenever you have a conversation or communicate with someone, the goal is to for you and your partner to be always on the same page. Whether the medium of communication is face-to-face, telephone, video conferencing, email, or text messaging, it’s important that all communication partners receive each other’s messages and understand them correctly.

But another basic principle of communication is that of least effort. All partners in a communication want to minimize the overall effort needed to achieve the communication goal. To that end, in any communication, people rely on explicit or implicit knowledge that they share with their communication partners. They also rely on signals that they receive from their partners to assess whether the communication has been successful so far or certain facts need clarification.

Any type of communication, whether face to face or remote, whether between two people or among groups of people, must establish common ground to ensure that the communication is efficient. In the absence of common ground, we could never use shortcuts in communication and we’d always have to describe precisely every single thing we’re referring to. The process of communication will proceed very slowly. Maybe the closest analogy of a conversation with no common ground is a conversation with an intelligent assistant, where you ask it for a pizza place, then get no answer when you continue the conversation with something like “What kind of pizza does it have?”

A lot of the times, grounding relies on signals received from our communication partners. For example, in a face-to-face conversation, a person may nod or say “I see” to confirm their understanding and allow the speaker to move on. Or, if the communication is unclear, they may ask a question or raise their eyebrows (or squint). The speaker will then have to solve the issue before moving on, thus ensuring that common ground has been established.

To establish common ground efficiently, communicators can use a variety of means. They can rely on intonation or body language, they can use gestures to point to objects in a common environment, or they may make references to concepts, facts, or people they know the audience is aware of.

For example:

  • On a hike you may point to an unknown flower species and say “How pretty it is!” and your partner will only know what you’re talking about because you’re pointing at the “it.” Later, you might mention “that flower” in the conversation and your partner will know which one it is.  
  • When talking about my experience in a particular restaurant, I might say to my friend “this reminds me of the soup Nazi” and he will know that I am talking about a particular Seinfeld episode because we both watched and enjoyed Seinfeld.
In a communication process, a main communicator (source) sends information in the form of words and gestures to one or more interlocutors through a communication channel. The communication channel represents the medium through which the communication is carried out (for example, in-person or email); how much information at any given moment can be sent depends on the communication channel. The communication can be more efficient if there is common ground between the communication partners.


Factors that Affect Grounding

There are several variables that influence communication efficiency and the ease of grounding:

  • Whether the communication is synchronous or asynchronous

Synchronous communication, in which all participants are simultaneously engaged in the process, is usually more favorable to establishing common ground than asynchronous communication. Notable examples of synchronous communication are live presentations or meetings or conversations (whether in person, on the telephone, through instant messaging, or through video conferencing). Contrast these methods with asynchronous ones such as texts and emails, memos, recorded presentations, videos, and so on.

In synchronous communication, it’s easy for people to understand when their communication partner is up to speed or needs further clarification, because, after each communication unit (such as a sentence) the main communicator can either implicitly or explicitly check with the communication partners to see if common ground has been achieved. (For example, in a face-to-face conversation, the speaker can look for implicit signals such as eye contact, body language, or gestures from conversation partner; they can also use questions such as “Right?” or “Do you get it?” and immediately answer any requests for clarification). In contrast, in an asynchronous communication (such as email or even text messages), the main communicator will have to usually wait for confirmation that the message has gotten through and was correctly understood. The unit of communication may also be bigger (for example, an email message will usually have several paragraphs, whereas in a conversation the unit of communication is shorter — a sentence or a word) and, when requests of clarification will come back, there will be a higher cost of recovery because the main communicator (or the source) will have to figure out precisely which part of their message was unclear and clarify it.

  • The medium through which communication is carried out

Different communication media have different bandwidths. For example, in face-to-face communication, beside words, the partners can use body language and gestures to help each other establish common ground. In in-person communication, they can also use the common context (such as the room in which both people are at the same time).

In general, the presence of an artifact that all parties can refer to during communication usually makes communication more efficient. This artifact could be created during the conversation (for example, on a whiteboard) or could be already existent. Think about the (perhaps outdated) task of giving directions to a stranger — it’s a lot easier to do so if they have a map or if you can draw on a piece of paper than if you are limited to using words.

  • Familiarity with the other parties involved in communication

Like in the joke in the beginning of the article — if you and your communication partners already have a lot in common, you can take advantage of that shared knowledge to make the communication very efficient. If you’re working with an established team of UX professionals, you won’t need to explain to them what expert reviews or usability testing are, but if you’re talking to a stranger on the street you probably will have to define those terms. (Sadly, due to UX vocabulary inflation, you may have to explain yourself when talking to UX professionals outside your team.)

  • The number of parties involved in the communication

Obviously, it’s a lot easier to communicate with one person than with a roomful of people. In order for the communication to be successful, we’ve seen that the recipient must understand the message. But when there are many communication partners, it becomes hard to ensure that common ground has been established with all of them. Maybe some people in the room will get that reference to Seinfeld, but maybe some won’t. Maybe some will understand your specialized lingo but maybe others won’t have a clue. You cannot check with every single person that they understood you. Because of that, a lot of communicators will need to design their communication to the lowest common denominator and not rely on common-ground helpers (such as personal history or common knowledge) that they share with part of the audience. The communication will thus become less efficient.

Common Ground and UX

Common ground is central to UX, and that is because UX is ultimately about communication: with our users and with our teammates. User-interface design is dialogue design.

Grounding with Users

The majority of the communication with our users is done asynchronously, through our products. Of course, we may communicate with our users through channels such as chat, social media, telephone, or email, but the bulk of our communication will usually be through the content on our website or application. Because of that, we won’t have the luxury of establishing common ground with every single user and we will have to be pretty generic in our communication so that we can reach everybody.

Tools like user testing and other types of user research as well as demographics and data from customer-service logs, analytics, and web searches are meant to provide us with an understanding of our communication partners at large. They ultimately build some of that common ground for us and enable us to make the communication more efficient by taking advantage of things that we know our users know.

All the UX work you’re doing in trying to understand your users ultimately enables you as a company to deliver products that encapsulate that common ground.

Grounding with Coworkers

As editor for, I review every single article that we publish. One of the most-common words that I see in our articles is ‘align’ — align with teammates, with stakeholders, with leadership. Even though this word now feels (at least to me) somewhat of a cliché, there is a reason why it is so popular — establishing common ground with the other members of your organization is crucial for the success of most UX-related activities and for the productivity of a team. And that’s what alignment is about. 

Whereas the main communication line with our users is asynchronous and impersonal, the interactions with our teammates are a lot more diverse and nuanced. We can interact face to face, in person (even if less so during a pandemic) or remotely, in small or large groups. We often have a lot of common history and context to rely on in these interactions. But, in many situations, these are not enough. People with different perspectives and backgrounds may have different understanding of the same term, process, or event. We need to make sure that we establish a clear common ground with everybody involved in a project.

How can you build common ground with coworkers?

  • Evangelizing UX will help people inside the organization understand what you mean when you talk about diary studies, design thinking, or the value of user-center design. You cannot simply assume that everybody in your organization shares this UX common ground. You need to investigate whether this knowledge exists in your organization and, if not, you need to build it.
  • Establishing a common vocabulary widely used by your team, if not your organization at large, will also go a long way in maximizing communication efficiency. After all, it doesn’t matter which definition of, say, customer experience and user experience you adopt, as long as everybody else on your team uses those words in the same way.  Take time and make sure that, for potentially ambiguous terms (‘CX’ and ‘design thinking’ are just a few examples) you bring everybody on the same page.
  • Use artifacts such a personas, customer-journey maps, empathy maps, service blueprints, UX roadmaps, and other types of maps.  In general, these visuals (and any others not listed, but that you may be able to invent) are meant to establish and record common ground. They can be easily referenced in further communications (so you won’t need to describe a user journey again and again, you can simply refer to the map) to increase communication efficiency, but they can also serve as organization memory, to keep track of what has been agreed upon or determined before. Their biggest forte is that they are concise and, unlike a document or a deck of slides, they don’t require your interlocutor to put in hours of reading.
  • Engage in one-to-one communication with people who are different than the rest of your team or may not share the same level of common ground. Remember, grounding depends on the size of the audience — it’s easier to reach it in one-to-one meetings than in group meetings. If you have a stakeholder who is particularly hard to convince or a newbie to a project, have a one-to-one meeting in which you can tailor the communication to their needs. You can more easily respond to their individual, perhaps unique questions or objections and clarify vocabulary that creates confusion if the communication is focused on a single person than if you’re catering to the needs of a larger group.  And, if possible, take advantage of a communication medium that has a larger communication bandwidth — prefer in-person to remote, face-to-face to telephone, ideally in a room where you can both reference some artifacts that are relevant to your discussion or can take advantage of sketching space like a whiteboard to clarify mental models and misunderstandings.
  • Learn about your coworkers so that you can create common-ground crutches. The more you know about someone, the more you can take advantage of that knowledge to make the communication efficient. If you know they are a numbers’ person, you can share statistics with them — not necessarily to mislead them, but to help them understand what you want them to.


Clark, H. H., & Brennan, S. E. 1991. Grounding in communication. In L. B. Resnick, J. M. Levine, & S. D. Teasley (eds.), Perspectives on socially shared cognition (p. 127–149). American Psychological Association.

Appendix: The Joke-Tellers’ Club

A city had a well-established joke-tellers’ club for people with an appreciation of sophisticated humor. One day, a prospective member was allowed to attend a meeting. About twenty members sat around a well-polished mahogany table, sipping glasses of vintage port. The beginning of the meeting passed in silence, as the members savored their port, but suddenly one member called out, “Number seventeen!” and the room erupted in laughter.

The prospective member turned to the person next to him and asked why everybody was laughing.  “Well,” said the existing member, “this is the joke-tellers’ club, so we have all heard these jokes many times before. Last year, the club president instituted a rule that, to save time, we would list all the jokes and from then on, members should just call out the number of the joke they want to tell, instead of saying the whole joke.”

“This sounds like fun,” said the new guy, “let me try: Number fifty-one!”

At this, all the members laugh louder than they have done all evening, slap their thighs, and one member ends up spluttering his drink.

“Wow,” says the prospective member, “why did they laugh that hard at my joke?”

“Oh,” says the club member, trying to stop himself from laughing, “we hadn’t heard that one before.”

[Alternate ending: The prospective member calls out, “Number twenty-three!” but the room is dead silent. He turns to the existing member and asks, “Why didn’t they laugh?” — to which the member replies, “You didn’t tell that joke right!”]